I just bought a new Toyota Corolla last year, and I love it. I'm a visiting nurse and have to find the homes of new clients all the time. I'd love to have one of those newfangled navigation systems that tell you how to get to specific addresses. It would make my life much easier. But it wasn't an option on the Corolla. And I don't want to trade in a perfectly good new car just to get a navigation system. Is there any way to get one put in? My Toyota dealer says he can't do it. -- Jane

TOM: Well, the Toyota dealer is right that it's pretty much impossible to add a factory Global Positioning System to a vehicle that was never designed to have one. But never fear, Jane -- you're not condemned to a life of rolling down the window and asking bums for directions.

RAY: There are several "aftermarket" navigation systems. The one we've been testing lately works extremely well. It's called the Magellan RoadMate, and it's a little box about the size of a 4-by-6 index card, and about an inch deep.

TOM: You can have it mounted permanently in your car, or, if you're part of a family that has several cars or you travel with friends, you can move it from car to car as needed.

RAY: It works just like the factory navigation systems. You enter a state, city and address, you push a button, and it guides you to your destination with a list of directions and a map on a video screen. There's also an optional electronic voice that says, "Hey, jerk, your next turn's coming up!" Or something like that.

TOM: It has all the extras that you typically get with a factory-installed system. It tells you what road you're currently on, how many miles to your next turn and how many miles to your ultimate destination. It lets you save destinations, like "Home," so you can always quickly set it to get you home from wherever you are. And it covers the entire continental United States.

RAY: It worked almost flawlessly for us. Our one complaint is that when you unplug it and move it from car to car, it often takes a few minutes to "locate itself." It has to check in with the GPS satellites and "lock" onto its own position before it can guide you. This sometimes took several minutes, while we sat around and twiddled our thumbs. There is a way to tell it your location, to speed up the process, but it's still an inconvenience.

TOM: The Magellan sells for about a thousand bucks. That's a lot. But it's less than the $1,500-$2,000 that most new car systems cost. And it has the advantage of being portable.

RAY: So, I think that's the perfect solution for you, Jane. You'll be able to spend more time nursing, and less time trying to properly refold maps!